1. Field of the Invention
This invention relates to the general field of erosion control, and more particularly to the method of forming erosion-control matting for use in the protection from moving water along stream banks, canals, irrigation conduits, sewage-treatment ponds, roadside ditches, coastal beaches and reltated applications.
Description of the Prior Art
The traditional form of erosion control has largely consisted or rock in various forms dumped or placed in a position to minimize the erosive effects of moving water.
There are many other forms of erosion mitigation including gabions, revetments, fences, seawalls, concrete in various forms and configurations, whole rubber tires both laid flat on the erosion surface (see patent #3,842,606 and 4,139,319) and stacked vertically one on top of the other, manufactured plastic sheathing and netting, and many other forms.
There are a number of claims relating to erosion control. As some examples of prior art one may refer to the following patents:
Twele: U.S. Pat. No. 3,455,112 PA0 Muhring: U.S. Pat. No. 4,002,034 PA0 Nielsen: U.S. Pat. No. 4,405,257 PA0 de Winter: U.S. Pat. No. 4,417,828 PA0 Smedley: U.S. Pat. No. 3,161,026 PA0 Danz: U.S. Pat. No. 3,426,536 PA0 Stiles: U.S. Pat. No. 3,842,606 PA0 Crow, Hansen: U.S. Pat. No. 4,375,928 PA0 Burg & Hoedt: U.S. Pat. No. 4,421,439 PA0 * More than 72 miles of south-shore Long Island is considered a high-risk zone for development with some locations being reclaimed by the sea at 6 feet per year. PA0 * Most of North Carolina is retreating at 3 to 6 feet per year. PA0 * Much of the Texas coastline is vanishing at an even faster rate. PA0 * California has had 30 relatively mild winters but, in the last 2 or 3 years, the winters have become more severe (possibly more normal) with more extensive coastal damage.
Although all the foregoing use some form of matting, none of them use rubber, or an interwoven rubber material combined with a cable or similar reinforcement along each side.
Still additional examples of prior art:
are further removed from the nature of this invention in that none of them uses a cut rubber matting, cable anchoring or varied weave densitites.
It is estimated that using the matting described in this invention it would cost approximately $75 per lineal foot to provide a high level of erosion control, heretofore not possible in the art.
The combination of qualities of flexibility, durability, easy installation and transportability will make this invention a favored material for emergency situations involving heavy rainstorms, spring runoff or other unusual high-energy water conditions which may create life threatening situations.
Another series of applications for this invention include coastal-erosion control. There are over 20,000 miles of coastline in the United States, much of it subjected to erosion and some of it, in recent years subjected to severe erosion, including 3,000 miles which are considered to be in critical danger.
One of the major concerns, particularly on the Atlantic coast, it that the water level has been rising and this increase has accelerated in the last 50 years to a rate of 11/2 feet per century. The most serious and persistent erosion occurs on low sandy beaches of the Atlantic and Gulf coasts.
On these gently sloping coastal plains, a small rise in sea level will increase the horizontal inland reach of the sea by many times its vertical measure. The average rate of long-term shoreline erosion varies greatly but, measured on an annual basis, it probably averages two to three feet per year. In some cases, it averages ten feet per year. Even if a precise measure of the rise of sea level can be argued, there is no doubt that most of the American shoreline is receding and the sea is advancing. In fact, the E.P.A. predicts that by the year 2,100, sea level will probably stand four feet above the present level.
A few examples of the deteriorating situation on our coastline include:
Many older shoreline developments have been protected by various hardening devices. This practice has yielded indisputable evidence that hard stabilization, groins and sea walls eventually degrade the beach. Many miles of beach, including such famous shorefronts as Daytona Beach, Virginia Beach, Myrtle Beach, Ocean City and Atlantic City are much narrower than they were or would have been in their natural state. In some long-developed and long-stabilized communites like Monmouth Beach, N. J., or Galveston, Tex., the beaches have essentially disappeared.
The coastal areas are of critical concern, particularly when it is predicted that, by 1990, 75% of the nation's population will be living within 50 miles of the coastline.
Existing control methods on the coastal beaches have, with very few exceptions, been universally disappointing. Rocks, groins and sea walls only seem to either increase the problem or shift it a few yards down the beach.
A further application for this invention is heavy construction. Wherever there is earthmoving and new artifical slopes created, there would be a potential for the matting. Examples would include highway interchanges and slope erosion control where the matting would prevent erosion and allow for revegetation to take place. The material could also be used in road or highway construction as an underlayer, supporting the upper layers of gravel and asphalt.
The matting would be particularly suitable adjacent to highways to control erosion runoff along the highway edges. Almost every depression adjacent to the highway requires some method of drainage control, usually concrete, where the matting would be a viable alternative. Further application would include mining operations, dam sites, and large projects where potential slope erosion is a factor or secure footings for the movement of equipment in mud and water is required.
One of the most comprehensive studies on erosion control was completed by: